public class Leetcode {
}

//leetcode:647:回文子串
class Solution1 {
    public int countSubstrings(String s) {
        int n = s.length();

        boolean[][] dp = new boolean[n][n];
        int ret = 0;
        for(int i = n-1; i >= 0; i--){
            for(int j = i; j < n; j++){
                if(s.charAt(i) == s.charAt(j)){
                    dp[i][j] = i+1 < j ? dp[i+1][j-1] : true;
                }
                if(dp[i][j]) ret++;
            }
        }
        return ret;
    }
}

//leetcode:5:最长回文子串
class Solution2 {
    public String longestPalindrome(String s) {
        int n = s.length();
        boolean[][] dp = new boolean[n][n];

        int len =1;
        int begin = 0;
        for (int i = n-1; i >= 0; i--) {
            for (int j = i; j < n; j++) {
                if(s.charAt(i) == s.charAt(j)){
                    dp[i][j] = i+1 < j ? dp[i+1][j-1] : true;
                }
                if(dp[i][j]){
                    if(j-i+1 > len){
                        len = j-i+1;
                        begin = i;
                    }
                }
            }
        }
        return s.substring(begin, begin + len);
    }
}